Laser machining apparatus and laser machining method

ABSTRACT

There is provided a laser machining apparatus, and a laser machining method using the same, which allows an installation area thereof to be reduced while improving working efficiency. The laser machining apparatus has a body portion having a plurality of laser irradiating sections and work mounting sections, a supplying stocker for supplying workpieces, and a discharging stocker for discharging the workpieces. The apparatus further comprises a supply-side transfer unit having work retaining tables capable of attaching/detaching the workpieces and of the same number with the laser irradiating sections, and moving the work retaining tables in the vertical and horizontal directions, and a discharge-side transfer unit having work retaining tables capable attaching/detaching the workpieces and of the same number with the laser irradiating sections, and moving the work retaining tables in the vertical and horizontal directions. The supply-side unit causes the plurality of supply-side work retaining tables to adsorb the workpieces from the supplying stocker one after another and moves these supply-side work retaining tables to the work mounting sections to place the workpieces thereon. The discharge-side unit causes the discharge-side work retaining tables to adsorb the workpieces which have been machined at the work mounting sections to move and discharge those workpieces to the discharging stocker.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a laser machining apparatus comprisinga plurality of laser irradiating sections and work mounting tablesdisposed so as to face to the laser irradiating sections and to a lasermachining method using the laser machining apparatus.

2. Description of Related Art

As a prior art laser machining apparatus, there has been known a lasermachining apparatus having a plate-like work supplying unit, asdisclosed in Japanese Patent Laid-open No. 2001-139170 for example,comprising work transferring means for transferring plate-likeworkpieces from a first work mounting section to a second work mountingsection, workpiece thickness detecting means for detecting whether ornot one workpiece is mounted on the second work mounting section, andwork transfer control means for controlling, when the workpiecethickness detecting means detects that a plurality of workpieces ismounted on the second work mounting section, the work transferring meansto return extra workpieces to the first work mounting section until whenone workpiece is left on the second work mounting section.

However, in case of the laser machining apparatus comprising a pluralityof work mounting sections, it takes time to transfer workpieces and themachining efficiency drops if the workpieces are to be transferred oneby one.

Still more, although the transfer time may be shortened by providing thesame number of second work mounting sections with the first workmounting sections and by taking out the workpieces from the plurality ofwork mounting sections in the same time, it is not practical because itrequires a large installation area for the laser machining apparatus.

BRIEF SUMMARY OF THE INVENTION

It is an object of the invention to solve the aforementioned problems byproviding a laser machining apparatus, and a laser machining method,that require no large installation area while improving its workefficiency.

A laser machining apparatus of the invention comprises:

-   -   a body portion of the laser machining apparatus having a        plurality of laser irradiating sections disposed in line in a        horizontal mono-axial direction and work mounting sections        disposed in line so as to face to the laser irradiating        sections;    -   a supplying stocker for supplying workpieces;    -   a discharging stocker for discharging the workpieces;    -   a supply-side transfer unit having work retaining means capable        of attaching/detaching the workpieces and of the same number        with the laser irradiating sections, and moving the work        retaining means in the vertical and horizontal directions; and    -   a discharge-side transfer unit having work retaining means        capable of attaching/detaching the workpieces and of the same        number with the laser irradiating sections, and moving the work        retaining means in the vertical and horizontal directions;        wherein the supplying stocker and the supply-side transfer unit        are disposed on one side of the axial direction of the work        mounting section and the discharging stocker and the        discharge-side transfer unit are disposed on the other side        thereof.

A laser machining method of the invention comprises:

-   -   a work retaining process of moving a plurality of supply-side        work retaining means in the vertical and horizontal directions        to adsorb and retain workpieces from one supplying stocker by        the respective work retaining means;    -   a work mounting process of moving the supply-side work retaining        means to the work mounting sections disposed so as to face to        the same number of the laser irradiating sections with the work        retaining means and of releasing the work retaining means to        place the workpieces retained by the plurality of work retaining        means to the work mounting sections; and    -   a work discharging process of adsorbing the plurality of        finished workpieces to the discharge-side work retaining means        after machining the workpieces placed on the work mounting        sections by the plurality of laser irradiating sections, moving        the work retaining means in the vertical and horizontal        directions and releasing the respective work retaining means to        discharge the plurality of workpieces retained by the        discharge-side work retaining means to one discharging stocker.

This arrangement allows the respective one of the work retaining meansof the supply-side transfer unit to retain a workpiece while machininganother workpiece retained by the work mounting section and when themachining ends, allows the respective one of the work retaining means ofthe discharge-side transfer unit to retain the workpiece which has beenmachined on the work mounting section. Then, after removing the finishedworkpiece from the work mounting section by the work retaining means, itallows the supply-side transfer unit to place the non-finished workpieceon the work mounting section to start machining and allows the finishedworkpiece retained by the work retaining means in the discharge-sidetransfer unit to be transferred to the discharging stocker.

Preferably, the inventive laser machining apparatus further compriseswork mounting tables which are capable of mounting workpieces and aredisposed at least in the supply-side transfer unit or the discharge-sidetransfer unit. This arrangement allows the workpieces to be temporarilyretained by the work mounting tables in retaining the workpieces by thework retaining means.

Further, the work mounting table disposed on the side of the supply-sidetransfer unit may be arranged so as to be movable in a mono-axialdirection and an interleaf mounting table whereon an interleaf may bemounted may be provided such that the interleaf mounting table isdisposed at the vertically intermediate position between the movablework mounting table and the supplying stocker.

Still more, the interleaf mounting table may be arranged to be movablein a mono-axial direction.

The work mounting table disposed on the side of the discharge-sidetransfer unit may be also arranged so as to be movable in a mono-axialdirection.

It is also possible to provide an interleaf removing and carrying-outunit for removing an interleaf placed on the non-finished workpiece fromthe workpiece and an interleaving unit for placing the interleaf on theworkpiece whose machining has been finished and to dispose the interleafremoving and carrying-out unit on the side of the supplying stocker andto dispose the interleaving unit on the side of the discharging stocker.

The inventive apparatus allows the machining efficiency to be improvedbecause it retains all workpieces to be machined next by the supply-sidework retaining means while machining other workpieces and it carries inor out a plurality of workpieces simultaneously by one time ofconveyance. Still more, the invention allows an installation area of theapparatus to be reduced by providing one each supplying and dischargingstockers for the plurality of work mounting sections (tables).

The specific nature of the invention, as well as other objects, uses andadvantages thereof, will clearly appear from the following descriptionand from the accompanying drawings wherein the same reference charactersdenote the same or corresponding parts throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view showing the whole of a laser machining apparatusaccording to a first embodiment of the invention.

FIG. 2 is a front view showing of a body portion of the laser machiningapparatus.

FIG. 3 is a front view showing the whole of a laser machining apparatusaccording to a second embodiment of the invention.

FIG. 4 is a plan view showing the whole of a laser machining apparatusaccording to a third embodiment of the invention.

FIG. 5 is a view taken in the direction of an arrow K in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Modes for carrying out the invention will be explained below withreference to exemplary embodiments thereof and the accompanyingdrawings.

FIRST EMBODIMENT

FIG. 1 is a front view showing the whole of a laser machining apparatusaccording to a first embodiment of the invention and FIG. 2 is a frontview showing a body of the laser machining apparatus. As shown in FIG.1, the inventive laser machining apparatus is composed of a body portionA thereof, a carrying-in unit B and a carrying-out unit C.

The structure of the body portion A will be explained at first withreference to FIGS. 1 and 2. An XY table 2 is disposed on a bed 1 of thebody portion A. The XY table 2 is movable on the bed 1 horizontally inthe X and Y directions. A plurality of (two in the figure) tables (workmounting sections) 3 is fixed on the XY table 2 separately by a distanceL in the Y-axis direction. A plurality of holes connected to a hollowsection inside is formed on the surface of the table 3. The hollowsections are connected to a vacuum source not shown so that the table 3can adsorb/release the workpiece 4.

A gate-type column 5 is fixed on the bed 1. A laser oscillator 6 ismounted on the column 5. An acoustic optical modulator 7 for switchingan optical path of a laser beam to a first optical path 30 a or to asecond optical path 30 b is disposed on an optical axis of the laseroscillator 6. A laser irradiating section composed of mirrors 8 a 1 and8 a 2 and a pair of optical scanner 9 a and fθ lens 10 a is disposed onthe first optical path 30 a. A laser irradiating section composed ofmirrors 8 b 1 and 8 b 2 and a pair of optical scanners 9 b and fθ lenslob is disposed on the second optical path 30 b.

Next, an operation of the body portion A of the laser machiningapparatus in machining workpieces will be explained. The acousticoptical modulator 7 switches the optical path of the laser beamoutputted from the laser oscillator 6 and causes the beam to enter theoptical scanner 9 a or 9 b through the mirrors 8 a 1 and 8 a 2 orthrough the mirrors 8 b 1 and 8 b 2. Then, the beam is positioned in theX and Y directions to machine the workpieces 4 by passing through the fθlens 10 a or the fθ lens 10 b. That is, it is possible to machine theworkpiece even when the workpiece 4 is put on only one table 3.

As shown in FIG. 1, a rail 11 permits a slider 12 in the carrying-inunit (supply-side transfer unit) B to reciprocate horizontally in theY-direction in the figure. One end of a lifter 13 capable ofextending/contracting in the vertical direction in the figure is fixedto the lower part of the slider 12. A plate 14 is fixed to the other end(edge) of the lifter 13. The plate 14 supports two work retaining tables(work retaining means) 16 a and 16 b movably in the vertical directionin the figure through an intermediary of guide rods 15. The workretaining tables 16 a and 16 b are disposed apart from each other in theY-axis direction by a distance L. A plurality of holes connected to ahollow section inside is made at the lower face of the work retainingtables 16 a and 16 b. The hollow sections are connected to a vacuumsource not shown so that the work retaining tables 16 a and 16 b canadsorb/release the workpiece 4. Springs 17 are provided contractedlybetween the work retaining table 16 a and the plate 14 and between thework retaining table 16 b and the plate 14, respectively, and bias thework retaining tables 16 a and 16 b away from the plate 14 to allow themotion of the plate 14 so that the plate 14 is not disturbed fromcontinuously moving the other work retaining table when either one ofthe two work retaining tables contacts with the work receiving table 18and its move is restricted.

The position of the slider 12 indicated by a solid line in the figureindicates its standby position (right end of its moving range) and theposition indicated by a dotted line indicates its supplying positiondescribed later. When the slider 12 is located at the supplyingposition, the work retaining tables 16 a and 16 b face, respectively, tothe tables 3 on the XY table 2 positioned at the work deliveringposition. It is noted that when the slider 12 is located at the standbyposition, the plate 14 is positioned at the rising end. A supplyingstocker 20 is disposed so as to face to the work retaining table 16 awhen the slider 12 is located at the standby position. Workpieces 4 arestacked on the upper face of the supplying stocker 20.

A rail 19 is disposed at the position in the vertical directioninterposed between the supplying stocker 20 and the work retainingtables 16 a and 16 b. A work receiving table (work mounting table) 18 ismovable on the rail 19 horizontally in the Y-direction. It is noted thata standby position of the work receiving table 18 is the position whenit is located at the left end of its moving range and at this time, thework receiving table 18 faces to the work retaining table 16 b when theslider 12 is located at its standby position. When the work receivingtable 18 is located at the right end of its moving range (receivingposition), the work receiving table 18 faces to the work retaining table16 a when the slider 12 is located at its standby position.

A rail 51 permits a slider 52 of the carrying-out unit (discharge-sidetransfer unit) C to reciprocate horizontally in the Y-direction in thefigure. One end of a lifter 53 capable of extending/contracting in thevertical direction in the figure is fixed to the lower part of theslider 52. A plate 54 is fixed to the other end (edge) of the lifter 53.The plate 54 supports work retaining tables (work retaining means) 56 aand 56 b movably in the vertical direction in the figure through anintermediary of guide rods 55. The work retaining tables 56 a and 56 bare disposed apart from each other in the Y-axis direction by thedistance L. A plurality of holes connected to a hollow section inside ismade at the lower face of the work retaining tables 56 a and 56 b. Thehollow sections are connected to a vacuum source not shown so that thework retaining tables 56 a and 56 b can adsorb/release the workpiece 4.Springs 57 are provided contractedly between the work retaining table 56a and the plate 54 and between the work retaining table 56 b and theplate 54 and bias the work retaining tables 56 a and 56 b away from theplate 54 to allow the motion of the plate 54 so that the plate 54 is notdisturbed from continuously moving the other work retaining table wheneither one of the two work retaining tables contacts with the workreceiving table and its move is restricted.

The position of the slider 52 indicated by a solid line in the figureindicates its standby position (left end of its moving range). When theslider 52 is located at the discharging position (not shown) at theright end of the moving range, the work retaining tables 56 a and 56 bface, respectively, to the tables 3 on the XY table 2 positioned at thework delivering position. It is noted that when the slider 52 is locatedat the standby position, the plate 54 is positioned at its rising end. Adischarging stocker 60 is disposed so as to face to the work retainingtable 56 a when the slider 52 is located at the standby position. Theupper face of the discharging stocker 60 is made flat so as to be ableto mount the workpieces 4 that have been machined.

A rail 59 is disposed at the position in the vertical direction betweenthe discharging stocker 60 a and the work retaining tables 56 a and 56b. A work receiving table (work mounting table) 58 is movable on therail 59 horizontally in the Y-direction. It is noted that the standbyposition of the work receiving table 58 is the position when it islocated at the right end of its moving range and at this time, the workreceiving table 58 faces to the work retaining table 56 b when theslider 52 is located at its standby position. When the work receivingtable 58 is located at the left end of its moving range (dischargingposition), the work receiving table 58 faces to the work retaining table56 a when the slider 52 is located at its standby position. It is notedthat a control section 50 controls the operation of the body portion A,the carrying-in unit B and the carrying-out unit C as well as aninterleaf carrying-out unit D and an interleaf carrying-in unit E andothers in a third embodiment described later, respectively.

Next, steps of the present embodiment for conveying the workpieces willbe explained. It is assumed that the workpieces 4 are mounted only onthe supplying stocker 20 and that the sliders 12 and 52 as well as thework receiving tables 18 and 58 are located at their respective standbypositions.

Step 1: Lower the plate 14 so that the lower face of the work retainingtable 16 a contacts with the workpiece 4 on the supplying stocker 20 andthen the work retaining table 16 a adsorbs the workpiece 4. While theother work retaining table 16 b contacts with the work receiving table18 at this time, the spring 17 contracts so that the motion of the plate14 continues.

Step 2: Raise the plate 14 to the standby position.

Step 3: Move the work receiving table 18 to the receiving position (theright end in its moving range).

Step 4: Lower the plate 14 so that the workpiece 4 retained by the workretaining table 16 a contacts with the work receiving table 18. Then,release the adsorption of the work retaining table 16 a to place theworkpiece 4 on the work receiving table 18.

Step 5: Raise the plate 14 and move the work receiving table 18 to itsstandby position.

Step 6: Lower the plate 14 until when the lower face of the workretaining table 16 b contacts with the workpiece 4 on the work receivingtable 18 and until when the lower face of the work retaining table 16 acontacts with the workpiece 4 on the supplying stocker 20, respectively,to cause the work retaining tables 16 a and 16 b to adsorb theworkpieces 4.

Step 7: Raise the plate 14.

The operations carried out in Steps 1 through 7 described above will bereferred to as a ‘work retaining process’ hereinafter.

Step 8: Move the XY table 2 to the work delivering position (supplyside) (move forward in FIG. 1).

Step 9: Move the slider 12 so that the work retaining tables 16 a and 16b face to the tables 3, respectively.

Step 10: Lower the plate 14 so that the workpieces 4 held by the workretaining tables 16 a and 16 b contacts with the tables 3.

Step 11: Turn on the vacuum source not shown to cause the tables 3 toadsorb the workpieces 4 and release the adsorption of the work retainingtables 16 a and 16 b.

Step 12: Raise the plate 14 and move the slider 12 to its standbyposition.

The operations carried out in Steps 9 through 12 described above will bereferred to as a ‘work mounting process’ hereinafter.

Step 13: Move the XY table 2 to a machining position (backward inFIG. 1) to start to machine the workpiece 4 and carry out the workretaining process (Steps 1 through 7 described above) to cause the workretaining tables 16 a and 16 b to retain the workpieces 4 on thesupplying stocker 20.

Step 14: After finishing the machining, move the XY table 2 to the workdelivering position (discharge side).

Step 15: Move the slider 52 at its standby position to the dischargingposition.

Step 16: Lower the plate 54 so that the lower face of the work retainingtables 56 a and 56 b contacts with the workpieces 4 on the tables 3.

Step 17: Stop the adsorbing operation of the tables 3 after adsorbingthe workpieces 4 by the work retaining tables 56 a and 56 b.

Step 18: Move the slider 52 to its standby position after raising theplate 54.

The operations carried out in Steps 14 through 18 described above willbe referred to as a ‘work carrying-out process’ (part of workdischarging process) hereinafter.

Step 19: Supply new workpieces 4 to the tables 3 through the workmounting process (Steps 9 through 12) to start machining. Thecarrying-in unit B causes the work retaining tables 16 a and 16 b toretain the workpieces 4 on the supplying stocker 20 through the workretaining process.

Meanwhile, the carrying-out unit C mounts the workpieces 4 retained bythe work retaining tables 56 a and 56 b to the discharging stocker 60through Steps 20 through 25 described below.

Step 20: Lower the plate 54 so that the workpiece 4 retained by the workretaining table 56 a contacts with the discharging stocker 60 and theworkpiece 4 retained by the work retaining table 56 b to the workreceiving table 58. Then, turn off the adsorption of the work retainingtables 56 a and 56 b to mount the workpieces 4 on the dischargingstocker 60 and the work receiving table 58. Although the other workretaining table 56 a contacts with the work receiving table 58 at thistime, the motion of the plate 54 is not disturbed because the spring 57contracts. It allows the workpiece 4 retained by the work retainingtable 56 a to contact with and to be placed on the discharge stocker 60and the workpiece 4 retained by the work retaining table 56 b to contactwith and to be placed on the work receiving table 58 even if the heightof the work receiving table 58 differs from that of the dischargestocker 60.

Step 21: Raise the plate 54 to its standby position.

Step 22: Move the work receiving table 58 to the discharging position(left end of its moving range).

Step 23: Lower the plate 54 to adsorb the workpiece 4 mounted on thework receiving table 58 by the work retaining table 56 a and then raisethe plate 54.

Step 24: Move the work receiving table 58 to its standby position.

Step 25: Lower the plate 54 so that the workpiece 4 retained by the workretaining table 56 a contacts with the uppermost workpiece 4 on thedischarging stocker 60 and then turn off the adsorption of the workretaining table 56 a. After that, raise the plate 54 and wait until whenmachining ends.

The operations carried out in Steps 20 through 25 will be referred to asa ‘work discharging process’ hereinafter. It is noted that the workreceiving tables 18 and 58 have been arranged so as to be movable in thehorizontal direction in the embodiment described above, the workreceiving table 18 may be fixed at its standby position. When the workreceiving table 18 is to be fixed, the slider 12 may be moved so thatthe work retaining table 16 a faces to the work receiving table 18,instead of moving the work receiving table 18 in Step 3 described above.The work receiving table 58 may be also fixed at its standby position inthe same manner.

SECOND EMBODIMENT

By the way, there is a case when workpieces are stacked by interleavinga soft sheet, e.g., a sheet of paper, resin or the like (hereinafterreferred to as an ‘interleaf’) between the workpieces in order toprevent scratch of the surface of the workpiece. A laser machiningapparatus suitable for such a case will be explained below. FIG. 3 is afront view showing the whole structure of the laser machining apparatusaccording to a second embodiment of the invention, wherein he samereference characters denote the same or corresponding parts with thosein FIGS. 1 and 2 and an explanation thereof will be omitted here.

In FIG. 3, a rail 62 is disposed at the position in the verticaldirection between the rail 19 and the supplying stocker 20. An interleafreceiving table (interleaf mounting table) 61 is disposed on the rail 62so as to be movable horizontally in the Y-direction. Similarly to thework receiving table 18, the standby position of the interleaf receivingtable 61 is the position when the interleaf receiving table 61 islocated at the left end of its moving range and at this time, theinterleaf receiving table 61 faces, through an intermediary of the workreceiving table 18, to the work retaining table 16 b when the slider 12is located at its standby position. The receiving position of theinterleaf receiving table 61 is the position when it is located at theright end of its moving range and at this time, the interleaf receivingtable 61 faces to the work retaining table 16 a when the slider 12 islocated at its standby position.

Next, steps for conveying the workpieces of the present embodiment willbe explained. It is assumed that the workpieces 4 and interleaves 4 sare alternately placed on the supplying stocker 20, i.e., in a manner ofinserting each interleaf 4 s between the workpieces 4. It is alsoassumed that the sliders 12 and 52, the work receiving tables 18 and 58and the interleaf receiving table 61 are located at their respectivestandby position. A workpiece 4 is mounted at the top of the supplyingstocker 20. It is also noted that a reference character (G) is added tothe number of each Step below in order to distinguish from the operationof the first embodiment.

Step G1: Lower the plate 14 so that the lower face of the work retainingtable 16 a contacts with the workpiece 4 to be machined on the supplyingstocker 20 and then to cause the work retaining table 16 a to adsorb theworkpiece 4.

Step G2: Raise the plate 14 to its standby position.

Step G3: Move the work receiving table 18 to the receiving position(right end of its moving range).

Step G4: Lower the plate 14 so that the workpiece 4 retained by the workretaining table 16 a contacts with the work receiving table 18. Then,release the adsorption of the work retaining table 16 a to place theworkpiece 4 on the work receiving table 18.

Step G5: Move the work receiving table 18 to its standby position afterraising the plate 14.

Step G6: Lower the plate 14 so that the lower face of the work retainingtable 16 b contacts with an interleaf 4 s on the supplying stocker 20and then cause the work retaining table 16 a to adsorb the interleaf 4s.

Step G7: Raise the plate 14 to its standby position.

Step G8: Move the interleaf receiving table 61 to the receivingposition.

Step G9: Lower the plate 14 so that the interleaf 4 s retained by thework retaining table 16 a contacts with the interleaf receiving table61. Then, release the adsorption of the work retaining table 16 a toplace the interleaf 4 s to the interleaf receiving table 61. Althoughthe work retaining table 16 b also drops together and contacts with aworkpiece on the work receiving table 18 at this time, the adsorption ofthe work retaining table 16 b is turned off and the motion of the otherwork retaining table 16 a is not disturbed because of the springs 17.

Step G10: Move the interleaf receiving table 61 to its standby positionafter raising the plate 14. It is noted that the state attained by StepsG6 through G10 is equivalent to the state completed by Step 5 using nointerleaf 4 s.

Step G11: Lower the plate 14 until when the lower face of the workretaining table 16 b contacts with the workpiece 4 on the work receivingtable 18 and until when the lower face of the work retaining table 16 acontacts with the workpiece 4 on the supplying stocker 20, respectively,and then cause the work retaining tables 16 a and 16 b to adsorb theworkpieces 4. The springs 17 absorb the difference of the movements ofthe both work retaining tables 16 a and 16 b at this time as describedabove. The same also applies to the cases below.

Step G12: Raise the plate 14.

The operations carried out in Steps G1 through G12 described above willbe referred to as an ‘interleaved work retaining process’ hereinafter.

Step G13: Move the XY table 2 to the work delivering position (moveforward in FIG. 3).

Step G14: Carry out the work mounting process, i.e., Steps 9 through 12in the first embodiment.

Step G15: As machining of the workpiece starts, the carrying-in unit Bretains the interleaf 4 s at the work retaining tables 16 a and 16 bthrough Steps G16 through G20 described below.

Step G16: Lower the plate 14 so that the lower face of the workretaining table 16 a contacts with the interleaf 4 s on the supplyingstocker 20 and then cause the work retaining table 16 a to adsorb theinterleaf 4 s.

Step G17: Raise the plate 14 to its standby position.

Step G18: Move the work receiving table 18 to the receiving position.

Step G19: Lower the plate 14 until when the lower face of the workretaining table 16 b contacts with the interleaf 4 s on the interleafreceiving table 61. Then, cause the work retaining table 16 b to adsorbthe interleaf 4 s. It is noted that the work retaining table 16 acontinues to adsorb the interleaf 4 s at this time.

Step G20: Raise the plate 14.

The interleaf is retained by the work retaining tables 16 a and 16 bthrough Steps G16 through G20 described above. Steps G16 through G20described above will be referred to as an ‘interleaf retaining process’hereinafter.

Step G21: After ending the machining, move the XY table 2 to the workdelivering position.

Step G22: The carrying-out unit C carries out a process of Steps G24through G39 described below after carrying out the work carrying-outprocess, i.e., Steps 14 through 18 in the first embodiment.

Step G23: The carrying-in unit B carries out the interleaved workretaining process after confirming that Step G22 has been finished andafter carrying out the work mounting process (the interleaf 4 s isplaced on the table 3 in this case). It is noted that in the workmounting process when the workpieces are the interleaves, thecarrying-in unit B places the interleaves 4 s retained by the workretaining tables 16 a and 16 b through the interleaf retaining processdescribed above to the table 3 by moving the plate 14 to the positionindicated by dot lines (the left end of its moving range) by means ofthe slider 12, by dropping the work retaining tables 16 a and 16 b onthe table 3 at the delivering position so that the interleaves 4 scontact with the table 3 and by turning off the adsorption.

Then, after waiting for a process in Step G26 described later to end,the carrying-in unit B carries out the work mounting process. It isnoted that machining starts when the work mounting process ends.

Step G24: Lower the plate 54 so that the finished workpiece 4 retainedby the work retaining table 56 a contacts with the discharging stocker60 and the workpiece 4 retained by the work retaining table 56 bcontacts with the work receiving table 58, respectively. Then, turn offthe adsorption of the work retaining tables 56 a and 56 b to mount theworkpieces 4 to the discharging stocker 60 and the work receiving table58, respectively.

Step G25: Raise the plate 14.

Step G26: After ending the process of Step G23, the carrying-out unit Ccarries out a work carrying-out process. That is, the carrying-out unitC moves the plate 54 to the left end of its moving range by means of therail 51, drops it so that the work retaining tables 56 a and 56 b adsorbthe interleaves 4 s and moves the plate 54 to its standby position.After that, the carrying-out unit C carries out an interleaved workdischarging process composed of Steps G27 through G39 described below.

Step G27: Lower the plate 54 so that the interleaf 4 s retained by thework retaining table 56 a contacts with the discharging stocker 60.Then, turn off the absorption of the work retaining table 56 a to placethe interleaf 4 s on the discharging stocker 60. It is noted that thework retaining table 56 b continues to retain the interleaf 4 s at thistime.

Step G28: Raise the plate 54.

Step G29: Move the work receiving table 58 to the discharging position.

Step G30: Lower the plate 54 so that the work retaining table 56 aadsorbs the workpiece 4 on the work receiving table 58 and then raisethe plate 54.

Step G31: Move the work receiving table 58 to its standby position.

Step G32: Lower the plate 54 to mount the workpiece 4 retained by thework retaining table 56 a on the discharging stocker 60 and theinterleaf 4 s retained by the work retaining table 56 b on the workreceiving table 58, respectively.

Step G33: Raise the plate 54.

Step G34: Move the work receiving table 58 to the discharging position.

Step G35: Lower the plate 54 so that the work retaining table 56 aadsorbs the interleaf 4 s on the work receiving table 58.

Step G36: Raise the plate 54.

Step G37: Move the work receiving table 58 to its standby position.

Step G38: Lower the plate 54 to place the interleaf 4 s retained by thework retaining table 56 a on the workpiece 4 on the discharging stocker60.

Step G39: Raise the plate 54 and wait until when machining is completed.

Preferably, the operations for adsorbing/placing the workpieces 4 or theinterleaf 4 s by the work retaining tables 16 a, 16 b, 56 b and 56 b maybe carried out reliably and quickly by providing elevator units to thesupplying stocker 20 and the discharging stocker 60 so that the heightof the uppermost workpiece 4 becomes the same with that of the workpiece4 or the interleaf 4 s mounted on the work receiving table 18 or 58 inthe both cases of the first and second embodiments.

THIRD EMBODIMENT

FIG. 4 is a plan view showing a structure of a laser machining apparatusaccording to a third embodiment of the invention and FIG. 5 is a view inthe direction of an arrow K in FIG. 4, wherein the same or correspondingparts with those in FIGS. 1 and 2 will be denoted by the same referencenumerals and an explanation thereof will be omitted here. It is notedthat a front view of the apparatus of the present embodiment issubstantially the same with that shown in FIG. 1.

An interleaf carrying-out unit (interleaf removing and carrying-outunit) D is disposed behind the carrying-in unit (supply-side transferunit) B in FIG. 1 and an interleaf carrying-in unit (interleaving unit)E is disposed behind the carrying-out unit (discharge-side transferunit) C in FIG. 1, respectively (see FIG. 4). Here, the interleafcarrying-out unit D is a unit for retaining an interleaf 4 s on aworkpiece 4 placed on the supplying stocker 20 and for placing it on aninterleaf discharging table 90. The interleaf carrying-in unit E is aunit for retaining the interleaf 4 s placed on an interleaf supplyingtable 91 to place it on a workpiece 4 mounted on the discharging stocker60. Because the structure of the interleaf carrying-out unit D is thesame with that of the interleaf carrying-in unit E, a subscript (a) isappended to the reference numerals denoting the parts of the interleafcarrying-out unit D and a subscript (b) is appended to those of theinterleaf carrying-in unit E. The interleaf carrying-in unit E will beexplained below.

As shown in FIG. 5, a rail 81 b which extends horizontally in the Xdirection in the figure supports a slider 82 b of the interleafcarrying-in unit E so as to be reciprocally movable. One end of a lifter83 b which is capable of extending/contracting in the vertical directionin the figure is fixed to the lower part of the slider 82 b. A plate 84b is fixed to the other end (edge) of the lifter 83 b. The plate 84 bsupports a work retaining table (work retaining means) 86 b so as to bemovable in the vertical direction in the figure through an intermediaryof guide rods 85 b. A plurality of holes connected to a hollow sectioninside is made at the lower face of the work retaining table 86 b. Thehollow section is connected to a vacuum source not shown. Springs 87 bare provided in contraction between the work retaining table 86 b andthe plate 84 b to bias the work retaining table 86 b away from the plate84 b.

The standby position of the slider 82 b is the position indicated by asolid line in the figure and the position indicated by a two-dot chainline in the figure is the interleaf supplying position. In the interleafsupplying position, the work retaining table 86 b is located at theposition facing to the discharging stocker 60, i.e., the positionoverlapping with the work retaining table 56 b at its standby position.It is noted that the plate 84 b is located at its rising end when theslider 82 b is located at its standby position.

The interleaf supplying table 91 is disposed at the position facing tothe slider 82 b at its standby position. Interleaves 4 s are stacked onthe interleaf supplying table 91.

Next, an operation of the interleaf carrying-in unit E will beexplained. The interleaf carrying-in unit E lowers the plate 84 b sothat the lower face of the work retaining table 86 b contacts with theinterleaf 4 s stacked on the interleaf supplying table 91 and causes thework retaining table 86 b to adsorb the interleaf 4 s. Then, it standsby while raising the plate 84 b to its standby position.

Receiving an operating command from the control section 50, theinterleaf carrying-in unit E moves the slider 82 b so that the workretaining table 86 b faces to the discharging stocker 60. Then, itlowers the plate 84 b so that the interleaf 4 s adsorbed by the workretaining table 86 b contacts with the workpiece 4 mounted on thedischarging stocker 60 and then releases the adsorption to place theinterleaf 4 s on the workpiece 4. After that, it raises the plate 84 bto return to its standby position. Then, it stands by while retaining anext interleaf 4 s on the work retaining table 86 b through Stepsdescribed above.

Because the work retaining table 86 b at the interleaf supplyingposition and the work retaining table 56 b at its standby positioninterfere each other as described above, the control section 50 controlsthe slider 82 b and the slider 52 precisely so that they do notinterfere each other. It is noted that the operation of the interleafcarrying-out unit D is the same with that of the interleaf carrying-inunit E described above and is readily understood from the operation ofthe interleaf carrying-in unit E, so that its explanation will beomitted here.

Next, work conveying steps of the present embodiment will be explainedwith reference to FIGS. 4 and 5 together with FIG. 1. It is noted thatwhile the steps in the first embodiment are applied here as they are,additional steps will be described by appending subscripts (a), (b) and(c) to Step Nos. It is assumed that the workpieces 4 are mounted only onthe supplying stocker 20 and the sliders 12, 52, 82 a and 82 b as wellas the work receiving tables 18 and 58 are located at their standbyposition, respectively.

Step 1: Lower the plate 14 so that the lower face of the work retainingtable 16 b contacts with a workpiece 4 to be machined on the supplyingstocker 20 and cause the work retaining table 16 b to adsorb theworkpiece 4.

Step 2: Raise the plate 14 to its standby position.

Step 3: Move the work receiving table 18 to the receiving position (theright end of its moving range).

Step 4: Lower the plate 14 so that the workpiece 4 retained by the workretaining table 16 b contacts with the work receiving table 18 andrelease the adsorption of the work retaining table 16 b to place theworkpiece 4 on the work receiving table 18.

Step 5: Raise the plate 14 and move the work receiving table 18 to itsstandby position.

Step 5 a: Move the slider 12 to dislocate the work retaining table 16 bfrom the position facing to the supplying stocker 20.

Step 5 b: Operate the interleaf carrying-out unit D to remove theinterleaf 4 s on the supplying stocker 20 and place the removedinterleaf 4 s on the interleaf discharging table 90.

Step 5 c: Return the slider 12 to its standby position.

Step 6: Lower the plate 14 until when the lower face of the workretaining table 16 b contacts with the workpiece 4 on the work receivingtable 18 and until when the lower face of the work retaining table 16 bcontacts with the workpiece 4 on the supplying stocker 20, respectively,and cause the work retaining tables 16 b and 16 b to adsorb theworkpieces 4.

Step 7: Raise the plate 14.

The operation carried out in Steps 1 through 7 and in Steps 5 a through5 c described above will be referred to as a ‘second work retainingprocess’ hereinafter.

Step 8: Move the XY table 2 to the work delivering position (moveforward in FIG. 1).

Step 9: Move the slider 12 so that the work retaining tables 16 b and 16b face to the tables 3, respectively.

Step 9 a: Operate the interleaf carrying-out unit D to remove theinterleaf 4 s on the supplying stocker 20 by adsorbing by the workretaining table 86 a.

Step 10: Lower the plate 14 so that the workpieces 4 retained by thework retaining tables 16 b and 16 b contact with the tables 3,respectively.

Step 11: Turn on the vacuum source not shown to cause the tables 3 toadsorb the workpieces 4 and release the adsorption of the work retainingtables 16 b and 16 b.

Step 12: Raise the plate 14 and move the slider 12 to its standbyposition.

The operations carried out in Steps 9 through 12 and Step 9 a describedabove will be referred to as a ‘second work mounting process’hereinafter.

Step 13: Start to machine the workpiece 4 and carry out the second workretaining process (Steps 1 through 7 and Steps 5 a through 5 c describedabove) so that the work retaining tables 16 b and 16 b retain theworkpieces 4 on the supplying stocker 20.

Step 14: After finishing the machining, move the XY table 2 to the workdelivering position.

Step 15: Move the slider 52 at its standby position to the dischargingposition.

Step 16: Lower the plate 54 so that the lower face of the work retainingtables 56 b and 56 b contacts with the workpieces 4 on the tables 3.

Step 17: Stop the adsorbing operation of the tables 3 after adsorbingthe workpieces 4 by the work retaining tables 56 b and 56 b.

Step 18: Move the slider 52 to its standby position after raising theplate 54.

That is, the ‘work carrying-out process’ carried out in Steps 15 through18 is the same with that in the first embodiment.

Step 19: Supply a new workpiece 4 to the table 3 through the second workmounting process and start machining. The carrying-in unit B causes thework retaining tables 16 b and 16 b to retain workpieces 4 to bemachined on the supplying stocker 20 through the second work retainingprocess.

Meanwhile, the carrying-out unit C mounts the finished workpieces 4retained by the work retaining tables 56 b and 56 b to the dischargingstocker 60 through Steps 20 through 25 described below.

Step 20: Lower the plate 54 so that the workpiece 4 retained by the workretaining table 56 b contacts with the discharging stocker 60 and theworkpiece 4 retained by the work retaining table 56 b contacts with thework receiving table 58, respectively. Then, turn off the adsorption ofthe work retaining tables 56 b and 56 b to mount the workpieces 4 to thedischarging stocker 60 and the work receiving table 58.

Step 21: Raise the plate 54 to its standby position.

Step 22: Move the work receiving table 58 to the discharging position(left end of its moving range).

Step 23: Lower the plate 54 so that the work retaining table 56 badsorbs the workpiece 4 mounted on the work receiving table 58 and thenraise the plate 54.

Step 24: Move the work receiving table 58 to its standby position.

Step 24 a: Move the slider 52 to dislocate the work retaining table 56 bfrom the position facing to the discharging stocker 60.

Step 24 b: Operate the interleaf carrying-in unit E to place theinterleaf 4 s retained by the work retaining table 86 b on the finishedwork on the discharging stocker 60.

Step 24 c: Return the slider 52 to its standby position.

Step 25: Lower the plate 54 so that the workpiece 4 retained by the workretaining table 56 b contacts with the uppermost interleaf 4 s on thedischarging stocker 60 and then turn off the adsorption of the workretaining table 56 a. After that, raise the plate 54 and wait until whenmachining ends.

It is needless to say that the same steps with those in the firstembodiment are carried out when no interleaf 4 s is interposed betweenthe workpieces 4 mounted on the supplying stocker 20. Although the thirdembodiment requires additional units and a larger installation area ascompared to the second embodiment, it is advantageous in that it enableswork efficiency to be improved considerably. It is noted that theinterleaves 4 s may be utilized effectively by transferring thoseinterleaves 4 s discharged to the interleaf discharging table 90 to theinterleaf supplying table 91.

It is also noted that the work receiving table 18 may be fixed at itsstandby position in the third embodiment similarly to the case of thefirst embodiment. When the work receiving table 18 is to be fixed, theslider 12 may be moved so that the work retaining table 16 b faces tothe work receiving table 18, instead of moving the work receiving table18 in Step 3 described above. The interleaf carrying-out unit D may beoperated while moving the slider 12. The work receiving table 58 may bealso fixed at its standby position in the same manner.

Still more, the machining accuracy may be improved by providing a workpositioning device in each of the supplying stocker 20, the workreceiving table 18 and the tables 3 in any embodiment of the firstthrough third embodiments. It is also possible to prevent misalignmentof the workpiece 4 or the interleaf 4 s effectively by providingadsorption means in the work receiving tables 18 and 58, respectively.

It is also possible to arrange so as to be able to machine a pluralityof workpieces simultaneously by disposing a half-mirror or a beamsplitter, instead of the acoustic optical modulator 7.

Further, although the work retaining tables 16 b and 16 b have beenmoved up and down by the lifter 13 in the embodiments described above,lifting unit may be provided at the work retaining tables 16 b and 16 b,respectively, so that they can move up and down, respectively. Althoughthe case of two tables 3 has been described, it is possible to machineworkpieces through the steps similar to those described above even whenthere are three tables or more. The present invention is also applicableto a case when a plurality of workpieces is mounted on one table.

While the preferred embodiments have been described, variations theretowill occur to those skilled in the art within the scope of the presentinventive concepts which are delineated by the following claims.

1. A laser machining apparatus, comprising: a body portion having aplurality of laser irradiating sections arranged in a horizontalmono-axial direction and work mounting sections disposed so as to faceto said laser irradiating sections; a supplying stocker for supplyingworkpieces; a discharging stocker for discharging the workpieces; asupply-side transfer unit having work retaining means capable ofattaching/detaching the workpieces and of the same number with saidlaser irradiating sections, and being capable of moving said workretaining means in the vertical and horizontal directions; and adischarge-side transfer unit having work retaining means capable ofattaching/detaching the workpieces and of the same number with saidlaser irradiating sections, and being capable of moving said workretaining means in the vertical and horizontal directions; wherein saidsupplying stocker and said supply-side transfer unit are disposed on oneside of the axial direction of said work mounting section and saiddischarging stocker and said discharge-side transfer unit are disposedon the other side thereof.
 2. The laser machining apparatus as set forthin claim 1, wherein respective one of said work retaining means of saidsupply-side transfer unit retains the workpiece while machining thenon-finished workpiece retained by said work mounting section; and whenthe machining ends, respective one of said work retaining means of saiddischarge-side transfer unit retains the workpiece whose machining hasbeen finished on said work mounting section to remove from said workmounting section, said supply-side transfer unit mounts a non-finishedwork piece on said work mounting section to start its machining, and theworkpiece retained by said work retaining means of said discharge-sidetransfer unit is transferred to said discharging stocker.
 3. The lasermachining apparatus as set forth in claim 1, further comprising workmounting tables capable of mounting workpieces thereon disposed at leastin one of said supply-side and discharge-side transfer units so thatsaid work mounting table temporarily retains the workpiece in retainingthe workpiece by said work retaining means.
 4. The laser machiningapparatus as set forth in claim 3, wherein said work mounting tables aredisposed in said supply-side transfer unit and in said discharge-sidetransfer unit; said work mounting table of said supply-side transferunit is arranged so as to be movable in a mono-axial direction; aninterleaf mounting table capable of placing interleafs thereon isprovided in said supply-side transfer unit; and said interleaf mountingtable is disposed at the vertically intermediate position between saidmovable work mounting table and said supplying stocker.
 5. The lasermachining apparatus as set forth in claim 4, wherein said interleafmounting table is arranged so as to be movable in a mono-axialdirection.
 6. The laser machining apparatus as set forth in claim 3,wherein said work mounting table is disposed at said discharge-sidetransfer unit and is arranged so as to be movable in a mono-axialdirection.
 7. The laser machining apparatus as set forth in claim 1,further comprising: an interleaf removing and carrying-out unit forremoving an interleaf placed on a non-finished workpiece; and aninterleaving unit for placing the interleaf on the workpiece which hasbeen machined; wherein said interleaf removing and carrying-out unit isdisposed on the side of said supplying stocker and said interleavingunit is disposed on the side of said discharging stocker.
 8. The lasermachining apparatus as set forth in claim 1, wherein said work retainingmeans is a work retaining table and two each of said work retainingtables are disposed at said supply-side transfer unit and at saiddischarge-side transfer unit, respectively.
 9. A laser machining method,comprising: a work retaining process of moving a plurality ofsupply-side work retaining means in the vertical and horizontaldirections to adsorb and retain workpieces from one supplying stocker bysaid plurality of work retaining means, respectively; a work mountingprocess of moving said supply-side work retaining means to work mountingsections disposed so as to face to the same number of laser irradiatingsections with the work retaining means, and releasing said workretaining means to place the workpieces retained by said plurality ofwork retaining means to said work mounting sections; and a workdischarging process of retaining a plurality of finished workpieces by aplurality of discharge-side work retaining means after machining theworkpieces placed on said work mounting sections by said plurality oflaser irradiating sections, moving said work retaining means in thevertical and horizontal directions, and releasing said respective workretaining means to discharge the plurality of workpieces retained bysaid discharge-side work retaining means to one discharging stocker. 10.The laser machining method as set forth in claim 9, comprising steps of:retaining the workpiece by respective one of said supply-side workretaining means while machining the non-finished workpiece retained bysaid work mounting section; and when the machining ends, retaining theworkpiece whose machining has been finished on said work mountingsection by respective one of said discharge-side work retaining means toremove them from said work mounting section, mounting a non-finishedworkpiece on said work mounting section by said supply-side workretaining means to start its machining, and transferring the workpieceretained by said discharge-side work retaining means to said dischargingstocker.
 11. The laser machining method as set forth in claim 9, whereinsaid work retaining process comprises a step of temporarily retainingthe workpiece by said work mounting table in retaining the workpiece bysaid plurality of supply-side work retaining means from said onesupplying stocker.
 12. The laser machining method as set forth in claim9, wherein said work discharging process comprises a step of temporarilyretaining the workpiece by the work mounting table in discharging theworkpiece from said plurality of discharge-side work retaining means tosaid one discharging stocker.
 13. The laser machining method as setforth in claim 9, wherein said supply-side and discharge-side workretaining means are two each work retaining tables and that said methodcomprises steps of: retaining workpieces by said two supply-side workretaining tables sequentially from one said supplying stocker; mountingtwo workpieces simultaneously on said work mounting sections by said twosupply-side work retaining tables retaining the workpieces; retainingthe two finished workpieces on said work mounting sectionssimultaneously by said two discharge-side work retaining tables; anddischarging the workpieces respectively retained by said twodischarge-side work retaining tables sequentially to one saiddischarging stocker.
 14. The laser machining method as set forth inclaim 13, wherein workpieces and interleaves are alternately stacked insaid supplying stocker, said method comprising steps of: retaining theworkpieces respectively by said two supply-side work retaining tableswhile temporarily receding an interleaf mounting table retaining oneinterleaf; retaining the interleaf on said interleaf mounting table andthe interleaf in said supplying stocker by said two supply-side workretaining tables after mounting the workpieces on said two supply-sidework retaining tables to said work mounting sections; after machiningtwo workpieces mounted on said work mounting sections by said laserirradiating sections, retaining the finished workpieces by said twodischarge-side work retaining tables and placing the two interleavesretained on said supply-side work retaining tables to said work mountingsections; after retaining the workpiece retained by one of said twodischarge-side work retaining tables by said work mounting table totemporarily recede and after discharging the workpiece retained by theother discharge-side work retaining table to said discharging stocker,retaining the two interleaves on said work mounting sections by saiddischarge-side work retaining tables, respectively; and afterdischarging one of the two interleaves retained by said work retainingtables to said discharging stocker, discharging the receded workpiece onsaid work mounting table to said discharging stocker by means of saidwork retaining table, moving the other interleave by means of said workmounting table and discharging it to said discharging stocker by meansof said work retaining table to sequentially and alternately dischargethe workpieces and interleaves to said discharging stocker.
 15. Thelaser machining method as set forth in claim 9, wherein the workpiecesand interleaves are alternately stacked in said supplying stocker; saidwork retaining process has a step of removing said interleaf from saidsupplying stocker by means of an interleaf removing and carrying-outunit; and said work discharging process has a step of supplying theinterleaf to the uppermost workpiece in said discharging stocker bymeans of an interleaf supplying unit.